Porphyry copper deposit in Washington, United States

Names and other identifiers

Tract name Cascade Arc (003pCu9014)
Site status deposit

Geographic location

Country United States
State or province Washington
Geographic location -120.381944444, 48.614722222
Geologic map unit -120.381944444, 48.614722222
Nearby data

Geologic information

Deposit type Porphyry copper
Age (Ma) 88Ma
Age determination method unknown
Age range 90–87 Ma
Age reference Singer and others (2008)
Minerals actinolite, anhydrite, arsenopyrite, azurite/malachite, biotite, bornite, chalcopyrite, chlorite, chrysocolla, copper, covellite, epidote, galena, goethite/limonite, kaolinite, magnetite, molybdenite, montmorillonite, pyrite, sericite, tourmaline
Associated rocks breccia, diorite, feldspar porphyry, hornfels, quartz diorite, quartz diorite porphyry, quartz feldspar porphyry, granite, granodiorite, andesite, dacite, graywacke, sandstone, siltstone, tuff, volcanic breccia
Tectonic setting continental margin
Stratigraphic age Late Cretaceous

Commodity and development information

Development status Prospect
Major commodities Cu
Tonnage (Mt) 135Mt
Cu grade (%) 0.36%
Mo grade (%) 0.006%
Au grade (g/t) 0.03g/t
Contained copper 490,000t
Gold-Moly ratio 5

Reference information

Comments 1991 potential resources estimate 454 Mt at 0.4% Cu and 0.34 g/t Au.
Study area name United States
References InterAmerican Resources Inc. (2001); Lasmanis (1995); Jones and Riedell (1995); Riedell and others (1996); Singer and others (2008)
Site reference U.S. Geological Survey National Mineral Resource Assessment Team (2002)
InterAmerican Resources Inc., 2001, InterAmerican Resources, Inc. announces significant land position in the Mazama porphyry copper deposit: InterAmerican Resources Inc. press release, November 9, 2001, 3 p., accessed [date unknown], at (Web page no longer available. See,+Inc.+Announces+Significant+Land+Position+in...-a079895264.)
Jones, B.K., and Riedell, K.B., 1995, Geology and geochemical zoning of the Mazama porphyry copper system, Okanogan County, Washington, in Pierce, F.W., and Bolm, J.G., eds., Porphyry copper deposits of the American Cordillera: Tucson, Arizona Geological Society Digest 20, p. 237–242.
Lasmanis, Raymond, 1995, Regional geological and tectonic setting of porphyry deposits in Washington State, in Schroeter, T.G., ed., Porphyry deposits of the northwestern Cordillera of North America: Canadian Institute of Mining, Metallurgy and Petroleum Special Volume 46, p. 77–102.
Riedell, K.B., Jones, B.K., and Cheney, E.S., 1996, Geology, geochemistry, and evolution of the Mazama porphyry copper-molybdenum-gold deposit, Okanogan County, Washington, in Coyner, A.R., and Fahey, P.L., eds., Geology and ore deposits of the American Cordillera: Geological Society of Nevada Symposium, Reno/Sparks, Nev., April 10–13, 1995 [Proceedings], v. 3, p. 1501–1520.
Singer, D.A., Berger, V.I., and Moring, B.C., 2008, Porphyry copper deposits of the world—Database and grade and tonnage models, 2008: U.S. Geological Survey Open-File Report 2008-1155, [45] p. and digital data, accessed December 31, 2013, at